TSPAN1 is a membrane protein of the tetraspanin superfamily, which are characterized by the presence of four conserved transmembrane regions. Tetraspanins have been involved in diverse processes such as cell activation and proliferation, adhesion and motility, differentiation, and cancer. Altered TSPAN1 expression has been associated with the progression in some neoplasms including hepatocellular carcinoma, colorectal, gastric and breast cancers.